{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "6767f1e2",
   "metadata": {},
   "source": [
    "-------\n",
    "* 学习人：罗海鑫\n",
    "* 时间：2021-11-29\n",
    "* week14\n",
    "* 学习线上资源：[python官方文档](https://www.python.org)\n",
    "* [博客_函数模块](https://cnblogs.com/xuzhichao/p/11570285.html)\n",
    "* [python-官方文档-函数模块](https://docs.python.org/3/tutorial/controlflow.html#definding-functions)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "ea0a5c41",
   "metadata": {},
   "source": [
    "# 本周学习目标\n",
    "> 1. 函数的定义\n",
    "> 2. 函数使用\n",
    "> 3. 函数的参数"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "cca2a540",
   "metadata": {},
   "source": [
    "## 函数的定义\n",
    "* 定义一个函数的一般步骤"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "333f4b2f",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 \n",
      "1 \n",
      "1 \n",
      "2 \n",
      "3 \n",
      "5 \n",
      "8 \n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1\n",
    "while a < 10:\n",
    "    print(a, end=' ')  # 0 1\n",
    "    a, b = b, a+b  # a = 1 a = 1 b = 2 a = 2 b = 3\n",
    "    print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "ae6ee5b5",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 \n",
      "1 \n",
      "1 \n",
      "2 \n",
      "3 \n",
      "5 \n",
      "8 \n",
      "13 \n",
      "21 \n",
      "34 \n"
     ]
    }
   ],
   "source": [
    "a, b = 0, 1\n",
    "while a < 50:\n",
    "    print(a, end=' ')\n",
    "    a, b = b, a+b  \n",
    "    print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "e864f8f3",
   "metadata": {},
   "outputs": [],
   "source": [
    "# ...... 我想重复使用某一个功能（避免重复造轮子）\n",
    "# ...... 使用的人可以不懂代码，只要会调用函数即可 function_name()"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "2de94ca8",
   "metadata": {},
   "source": [
    "> 1. 定义函数的一般方法：\n",
    "...\n",
    "\n",
    "def function_name(): # 1. function_ name 遵循变量定义的规则 区别数学函数==> f(x)   f可改，可定义名称 python函数可以自定义名称\n",
    "   \"\"\"函数的注释\"\"\" # 2. 函数的注释可以和使用者交流\n",
    "   函数体        # 3. 函数体要和定义函数保持一定的tab缩进\n",
    "..."
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "id": "35683648",
   "metadata": {
    "scrolled": false
   },
   "outputs": [],
   "source": [
    "def fib(n):    # write Fibonacci series up to n\n",
    "    \"\"\"Print a Fibonacci series up to n.\"\"\"\n",
    "    a, b = 0, 1\n",
    "    while a < n:\n",
    "        print(a, end=' ')\n",
    "        a, b = b, a+b\n",
    "    print()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "c857d0c1",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 \n"
     ]
    }
   ],
   "source": [
    "fib(10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "b0b2e73a",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 \n"
     ]
    }
   ],
   "source": [
    "fib(50)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "d0f4a1f6",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "0 1 1 2 3 5 8 13 21 34 55 89 \n"
     ]
    }
   ],
   "source": [
    "fib(100)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "fdce269c",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 1.写一个函数 实现hello world\n",
    "# 2.写一个函数 实现hello username"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "id": "213dae57",
   "metadata": {},
   "outputs": [],
   "source": [
    "def hello():\n",
    "    \"\"\"打印你好\"\"\"\n",
    "    print(\"hello,world!\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "f8fd187c",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello,world!\n"
     ]
    }
   ],
   "source": [
    "hello()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 36,
   "id": "2881a403",
   "metadata": {},
   "outputs": [],
   "source": [
    "def hello_user(username):      # 形式参数\n",
    "    \"\"\"打印，你好，xxx同学~\"\"\"                #处于服务状态\n",
    "    print(\"你好,\"+username.title()+\"同学！\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 35,
   "id": "f5900ac6",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "你好,Tf同学！\n"
     ]
    }
   ],
   "source": [
    "hello_user(\"TF\") # 实际参数"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3e6f6d65",
   "metadata": {},
   "source": [
    "* 思考：函数是否必须有 参数？\n",
    "* 注意：\n",
    "> 1. 在第一行定义函数中，不需要任何信息就能完成工作，因此括号是空的（即便如此，括号必不可少！）\n",
    "> 2. 要调用函数，可以依次指定函数名以及括号括起的必要信息。在第五行代码中，因为此函数greet_uesr()括号中不需要任何信息，只需要输入greet_uesr（）即可。和预期效果一样，打印Hello！："
   ]
  },
  {
   "cell_type": "markdown",
   "id": "1c555d51",
   "metadata": {},
   "source": [
    "##  3.函数的参数\n",
    "\n",
    "\n",
    "\n",
    "> 1. 形式参数\n",
    ">> 1. 定义函数时，写在 function_name 括号里面的参数\n",
    ">> 2. 在定义函数时，形式参数不占用空间\n",
    "> 2. 实际参数\n",
    ">> 1.调用函数时，写在 function_name 括号里面的参数\n",
    ">> 2. 在使用函数时，形式函数 被 分配空间，变为实际函数"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 38,
   "id": "fe802e87",
   "metadata": {},
   "outputs": [],
   "source": [
    "def describe_pet(animal_type,pet_name): # animal_type,pet_name 是形式参数 形参\n",
    "    \"\"\"显示宠物信息\"\"\"\n",
    "    print(\"\\nI have a\" + animal_type + \".\")\n",
    "    print(\"My\" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 39,
   "id": "036b9079",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"dog\",\"豆豆\") # \"dog\",\"豆豆\" 实际参数 实参"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 40,
   "id": "f0961d19",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have a豆豆.\n",
      "My豆豆's name is Dog.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\",\"dog\")"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a2429f1a",
   "metadata": {},
   "source": [
    "* 当函数具有多个参数时\n",
    "\n",
    "> 1. 位置参数\n",
    ">> 1. 形式参数有先后顺序，函数调用过程中应考虑参数的先后顺序，避免出现顺序出错的笑话\n",
    ">> 2. 调用函数过程中要考虑形式参数的个数\n",
    "> 2. [关键字参数](Keyword Arguments)\n",
    ">> 1. 调用函数时，通过赋值的方式传递给定义好的形参变量数据\n",
    ">> 2. 关键字参数不考虑先后顺序，因为是指定变量赋值\n",
    "> 3. [默认参数](Default Argument Values)\n",
    ">> 1. 在形式参数中提前预先设置一个用户可能使用的参数值\n",
    ">> 2. 用户在使用/调用函数时，可以省略不给默认参数赋值\n",
    ">> 3. 用户给默认参数赋值，将替换默认参数的值\n",
    ">> 4. 可节省操作"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 41,
   "id": "f3fcec54",
   "metadata": {},
   "outputs": [],
   "source": [
    "def describe_pet(animal_type,pet_name): # animal_type,pet_name 是形式参数 形参\n",
    "    \"\"\"显示宠物信息\"\"\"\n",
    "    print(\"\\nI have a\" + animal_type + \".\")\n",
    "    print(\"My\" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 42,
   "id": "d5f0e7e5",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "describe_pet() missing 1 required positional argument: 'pet_name'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-42-a70f5cbb422b>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mdescribe_pet\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"dog\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: describe_pet() missing 1 required positional argument: 'pet_name'"
     ]
    }
   ],
   "source": [
    "describe_pet(\"dog\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 44,
   "id": "65c058f1",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "# 在使用 descri_pet() 函数时 需要考虑 参数的位置，从而进行参数数据的输入（实参的调用）\n",
    "describe_pet(\"dog\",\"豆豆\") # 要根据 形式参数的位置先后顺序 先写animal_type,再写pet_name "
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 43,
   "id": "4d5b64ce",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "describe_pet() takes 2 positional arguments but 4 were given",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-43-e59cc42637a1>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mdescribe_pet\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"dog\"\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;34m\"cat\"\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;34m\"豆豆\"\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;34m\"乐乐\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: describe_pet() takes 2 positional arguments but 4 were given"
     ]
    }
   ],
   "source": [
    "describe_pet(\"dog\",\"cat\",\"豆豆\",\"乐乐\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 46,
   "id": "5481febb",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "# 关键字参数使用\n",
    "\n",
    "describe_pet(animal_type=\"dog\",pet_name=\"豆豆\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 69,
   "id": "77202652",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 默认参数\n",
    "def describe_pet(pet_name,animal_type=\"dog\"): \n",
    "    \"\"\"\n",
    "    显示宠物信息\n",
    "    \n",
    "    通过打印的方式显示宠物类型和宠物名称\n",
    "    参数信息：\n",
    "    pet_name： 是一个字符串，宠物名称\n",
    "    animal_type: 是一个字符串，宠物类型\n",
    "    \"\"\"\n",
    "    print(\"\\nI have a\" + animal_type + \".\")\n",
    "    print(\"My\" + animal_type + \"'s name is \"+pet_name.title() + \".\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 50,
   "id": "134f8b78",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have adog.\n",
      "Mydog's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 51,
   "id": "bc1f47d1",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "\n",
      "I have acat.\n",
      "Mycat's name is 豆豆.\n"
     ]
    }
   ],
   "source": [
    "describe_pet(\"豆豆\",\"cat\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 70,
   "id": "11024a24",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on function describe_pet in module __main__:\n",
      "\n",
      "describe_pet(pet_name, animal_type='dog')\n",
      "    显示宠物信息\n",
      "    \n",
      "    通过打印的方式显示宠物类型和宠物名称\n",
      "    参数信息：\n",
      "    pet_name： 是一个字符串，宠物名称\n",
      "    animal_type: 是一个字符串，宠物类型\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(describe_pet)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 55,
   "id": "97deba9a",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello\n",
      "hello\n"
     ]
    }
   ],
   "source": [
    "print(\"hello\")\n",
    "print(\"hello\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 57,
   "id": "c9c6ce49",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello \n",
      " hello\n"
     ]
    }
   ],
   "source": [
    "print(\"hello\",\"\\n\",\"hello\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 58,
   "id": "056a7cdb",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "hello\n",
      "hello\n"
     ]
    }
   ],
   "source": [
    "print(\"hello\",\"\\n\",\"hello\",sep=\"\")  #  删除空格"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 53,
   "id": "a0f307ee",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Help on built-in function print in module builtins:\n",
      "\n",
      "print(...)\n",
      "    print(value, ..., sep=' ', end='\\n', file=sys.stdout, flush=False)\n",
      "    \n",
      "    Prints the values to a stream, or to sys.stdout by default.\n",
      "    Optional keyword arguments:\n",
      "    file:  a file-like object (stream); defaults to the current sys.stdout.\n",
      "    sep:   string inserted between values, default a space.\n",
      "    end:   string appended after the last value, default a newline.\n",
      "    flush: whether to forcibly flush the stream.\n",
      "\n"
     ]
    }
   ],
   "source": [
    "help(print)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e7f56629",
   "metadata": {},
   "source": [
    "-------\n",
    "参数使用过程中的思考问题：\n",
    "> 1. 思考：关键字参数（调用函数) 和 位置参数（调用函数） 是否可以一起使用？（可以）\n",
    ">> 1. positional argument follows keyword argument(位置参数<font style=\"color:red\">均</font>要放在关键字参数前面)\n",
    ">> 2. test1() got multiple values for argument 'x'(映射，不能出现，multiple values（多重值）)\n",
    "> 2. 定义函数：默认参数（定义参数）和非默认参数（定义参数）的先后关系\n",
    ">> 1. non_default argument follows default argument(非默认参数<font style=\"color:red\">均</font>要放在moren参数前面)\n",
    "----------\n",
    "* 以下为测试代码：\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 61,
   "id": "ba381e09",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 案例1：\n",
    "def test1(x,y,z):\n",
    "    \"\"\"打印x,y,z的值\"\"\"\n",
    "    print(x)\n",
    "    print(y)\n",
    "    print(z)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 63,
   "id": "a4c917d7",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (<ipython-input-63-414cb715edad>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-63-414cb715edad>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    test1(x=2,3,y=4)\u001b[0m\n\u001b[1;37m              ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "test1(x=2,3,y=4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 62,
   "id": "85a0c306",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "test1(2,y=3,z=4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 64,
   "id": "8a7c7066",
   "metadata": {},
   "outputs": [
    {
     "ename": "SyntaxError",
     "evalue": "positional argument follows keyword argument (<ipython-input-64-7429723d6f7c>, line 1)",
     "output_type": "error",
     "traceback": [
      "\u001b[1;36m  File \u001b[1;32m\"<ipython-input-64-7429723d6f7c>\"\u001b[1;36m, line \u001b[1;32m1\u001b[0m\n\u001b[1;33m    test(2,y=3,4)\u001b[0m\n\u001b[1;37m               ^\u001b[0m\n\u001b[1;31mSyntaxError\u001b[0m\u001b[1;31m:\u001b[0m positional argument follows keyword argument\n"
     ]
    }
   ],
   "source": [
    "test(2,y=3,4)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 65,
   "id": "982245b6",
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "2\n",
      "3\n",
      "4\n"
     ]
    }
   ],
   "source": [
    "test1(2,z=4,y=3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 66,
   "id": "b9cff224",
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "test1() got multiple values for argument 'x'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-66-abf767fdec53>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mtest1\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m2\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0mx\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m3\u001b[0m\u001b[1;33m,\u001b[0m\u001b[0my\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;36m1\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: test1() got multiple values for argument 'x'"
     ]
    }
   ],
   "source": [
    "test1(2,x=3,y=1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 68,
   "id": "c4fb8bb5",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 案2：\n",
    "def test1(x,z,y=3):\n",
    "    \"\"\"打印x,y,z的值\"\"\"\n",
    "    print(x)\n",
    "    print(y)\n",
    "    print(z)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "53e7bf6d",
   "metadata": {},
   "source": [
    "## 4. 课本练习实践\n",
    "> 1. 总结函数的优势\n",
    "> 2. 预习课本第四章函数与模块\n",
    ">> 1. 完成课本元音字母实践\n",
    ">> 2. 浏览模块，创建模块和调用模块，了解 PEP 8 python国际代码标准"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 72,
   "id": "09be15fd",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowels(word):\n",
    "    \"\"\"判断输入文本出现的元音字母有哪些\"\"\"\n",
    "    vowels = set(\"aeiou\")\n",
    "    word = set(word)\n",
    "    print(vowels & word)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "691b3487",
   "metadata": {},
   "outputs": [],
   "source": [
    "search4vowels()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "id": "e4d167ba",
   "metadata": {},
   "outputs": [],
   "source": [
    "# 课本实践\n",
    "def search4vowels(phrase:str) -> set:\n",
    "    \"\"\"Return any vowels found in a supplied phrase.\"\"\"\n",
    "    vowels = set(\"aeiou\")\n",
    "    return vowels.intersection(set(phrase))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "id": "2e224014",
   "metadata": {},
   "outputs": [],
   "source": [
    "def search4vowels(phrase:str,letter:str = 'aeiou') -> set:\n",
    "    \"\"\"Return a set of the 'letters' found in 'phrase'.\"\"\"\n",
    "    return set(letters).intersection(set(phrase))"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a22f3e95",
   "metadata": {},
   "source": [
    "### 函数的优势\n",
    "> 1. 可以减少重复操作\n",
    "> 2. 使代码的逻辑思路更加清晰,将复杂的问题分成更简单的部分\n",
    "> 3. 使代码的可读性更强"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "83c476e9",
   "metadata": {},
   "source": [
    "# 2.下周预告\n",
    "## 2.1 函数返回值\n",
    "## 2.2 模块介绍"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "id": "c570631a",
   "metadata": {},
   "outputs": [],
   "source": []
  }
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